Move suggests Nintendo may launch NX in 2016, analyst says

TOKYO—Nintendo Co. has begun distributing a software development kit for its new NX videogame platform, people familiar with the matter said, suggesting the company is on track to introduce the product as early as next year.

The kit is used by third-party software developers to modify existing games for the platform or create new ones. Videogame console makers such as Nintendo like to have popular game titles ready when they start...